The formation of a molded member about an embedded or partially embedded element so as to form an integrated assembly is known and has many applications. The element is generally inserted into a mold cavity and arranged in some specified spatial configuration within the mold cavity prior to molding wherein a molten material, such as a resin based thermoplastic, is injected, compressed and allowed to harden before the integrated assembly is removed from the mold. In some applications, the embedded elements protrude from the molded member for mounting or interfacing the integrated assembly. In electrical applications for example the embedded clement may be a plurality of electrically conducting elements such as metallic leads, which form a portion of an electrical circuit within the molded member. The leads may also include an exposed conducting surface for contacting a conducting wiper or a protruding lead for interfacing with an electrical system. In electrical applications, the molded member retains the electrically conducting leads in some isolated electrical circuit configuration and the insulating property of the molded member electrically insulates the isolated conducting leads from one another.
In the past, the insertion and arrangement of a plurality of elements in a mold cavity prior to injection of the molten material has been simplified by interconnecting the plurality of elements with links to form a unitary member, which is more readily inserted into and arranged within the mold cavity than are a plurality of individual elements. In electrical applications for example a plurality of electrical leads arc interconnected by links to form a unitary lead frame, which may be fabricated from a sheet of conducting material in a stamping process, wherein the unitary lead frame is positioned in the mold cavity prior to molding. After the injected molten material cures or hardens, the integrated assembly is removed from the mold and further processed to separate and electrically isolate the individual leads that form the unitary lead frame. One method of separating the leads is to sever the links that interconnect the leads after the molding process with a punch, which is driven through the link and in some instances through both the link and the molded member. Another method, disclosed in U.S. Pat. No. 5,038,468 to Wanatowicz, severs the links with an arrangement of mold plates having a punch extendable toward a die after the unitary lead frame is inserted into the mold cavity but before injection of the molten material, which is injected into the cavity while the punch remains extended toward the die and in contact with the severed lead frame. Both prior art methods of separating the leads of the unitary lead frame however result in exposure of portions of the conducting leads on both opposing sides of the integrated assembly. More specifically, in the case where separation occurs after molding, a hole remains extending through the molded member and the severed unitary member exposing at least a sectional portion of the leads. In the case where separation occurs prior to molding, opposing surfaces of the lead frame are exposed by openings remaining on the molded member where the punch and die were positioned during injection of the molten material. Many applications however require that at least one side of the conducting leads, or at least an area about the severed link, be covered by the molded material to protect the conducting leads from moisture, corrosive materials such as salt and other degrading environmental hazards.
In view of the discussion above, there exists a demonstrated need for an advancement in the art of embedding elements in a molded member.